1887

Abstract

Summary: The and genes encoding formamidase and a putative regulatory protein, respectively, from the methylotrophic bacterium were recloned with additional flanking DNA (pSW1). encoding a weakly hydrophilic protein containing an N-terminal signal sequence, was identified upstream of The derived amino acid sequence of mature FmdC (M 39204) showed that it was rich in -sheet and aromatic amino acids, and exhibited significant similarities to several outer-membrane porins from other bacteria. Cell fractionation studies showed that the protein was located in the outer membrane. Mature FmdC was purified and shown to consist of a single type of subunit ( 40000) with the predicted N-terminal amino acid sequence (GATISF-). SDS-PAGE and Western blotting of cells grown in continuous culture under various conditions showed that mature FmdC was induced by formamide, acetamide and urea, repressed by excess ammonia, and over-expressed during prolonged growth under formamide limitation. It is concluded that mature FmdC is a porin involved in the transport of short-chain amides and urea through the outer membrane of under conditions where these nitrogen sources are present at very low concentration.

Funding
This study was supported by the:
  • Collaborative Awards in Science and Engineering studentships (UK Science and Engineering Research Council)
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1997-07-01
2021-08-01
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